Anode assembly, contact strips, electrochemical cell, and methods to use and manufacture thereof

ABSTRACT

Provided herein are anode assembly, conductive contact strips, electrochemical cells containing the anode assembly and the conductive contact strips, and methods to use and manufacture the same, where the anode assembly includes a plurality of V-shaped, U-shaped, or Z-shaped elements positioned outside the anode shell and in electrical contact with the anode.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit to U.S. Provisional Patent ApplicationNo. 62/341,941, filed May 26, 2016, and U.S. Provisional PatentApplication No. 62/442,163, filed Jan. 4, 2017, which are bothincorporated herein by reference in their entirety in the presentdisclosure.

BACKGROUND

Electrolytic cells contain an anode chamber that contains an anode, acathode chamber that contains a cathode, and one or more ion exchangemembranes such as anion exchange membrane and/or cation exchangemembrane interposed between the anode and the cathode. Both the anodeand the cathode may contain a series of supports that may be used tomount the anode across the open face of the anode chamber and mount thecathode across the open face of the cathode chamber. Current is injectedinto the outer surface of the anode chamber which then flows through theanode support bars. After passing through the anode, the membrane, andthe cathode, the current flows through the cathode supports bars, andout the back surface of the cathode chamber. The voltage distributionand the resultant current flow from the anode current bars/anodeinterface to the cathode/cathode current bars interface may impact theperformance and reliability of the electrochemical (e.g. chloralkali)cell significantly. Therefore, there is a need for an optimum anodeassembly that may result in a uniform current flow across the cellleading to minimized cell voltage and high membrane reliability.

SUMMARY

In one aspect, there is provided an electrochemical cell, comprising acathode shell, a cathode positioned inside the cathode shell, an anodeshell, an anode positioned inside the anode shell, and one or more ionexchange membranes, wherein the one or more ion exchange membranes aredisposed between the anode shell and the cathode shell; and a pluralityof V-shaped, U-shaped, or Z-shaped elements positioned outside the anodeshell and in electrical contact with the anode.

In some embodiments of the foregoing aspect, each of the V-shaped, theU-shaped, or the Z-shaped elements comprises an apex and a base. In someembodiments of the foregoing aspect and embodiment, each of the V-shapedor the U-shaped elements comprises two legs of equal length meeting atthe apex. In some embodiments of the foregoing aspect and embodiments,each of the V-shaped or the U-shaped elements comprises two legs ofunequal length meeting at the apex. In some embodiments of the foregoingaspect and embodiments, each of the V-shaped, the U-shaped, or theZ-shaped elements is made of a sheet of explosion bonded or lasercladded Ni—Ti (nickel-titanium). In some embodiments of the foregoingaspect and embodiments, each of the bases of the V-shaped, the U-shaped,or the Z-shaped elements is metallurgically attached to the outside ofthe anode shell bringing it in electrical contact with the anode.

In some embodiments of the foregoing aspect and embodiments, the apexesof the V-shaped, the U-shaped, or the Z-shaped elements compriseconductive contact strips; are coated with nickel, copper, or iron;cladded with nickel, copper, or iron; sprayed with nickel, copper, oriron; bonded with nickel, copper, or iron; or combinations thereof. Insome embodiments of the foregoing aspect and embodiments, the conductivecontact strips comprise explosion bonded Ni—Ti, explosion bonded Cu—Ti(copper-titanium), laser cladded Cu—Ti, or laser cladded Ni—Ti. In someembodiments of the foregoing aspect and embodiments, the conductivecontact strips provide electrical continuity between the anode shell ofthe electrochemical cell with a cathode shell of an adjacentelectrochemical cell when the electrochemical cells are stacked into anelectrolyzer.

In one aspect, there is provided an electrochemical cell, comprising acathode shell, a cathode positioned inside the cathode shell, an anodeshell, an anode positioned inside the anode shell, and one or more ionexchange membranes, wherein the one or more ion exchange membranes aredisposed between the anode shell and the cathode shell; and a pluralityof V-shaped, U-shaped, or Z-shaped elements positioned outside the anodeshell, wherein each of the V-shaped, the U-shaped, or the Z-shapedelements comprises an apex and a base, and wherein the apexes of theV-shaped, the U-shaped, or the Z-shaped elements comprise conductivecontact strips or wherein the apexes of the V-shaped, the U-shaped, orthe Z-shaped elements are coated, cladded, sprayed, or bonded with aconductive metal. In some embodiments, the conductive metal is same asthe cathode shell metal including, but not limited to, nickel, copper,or iron such as an iron alloy, e.g. stainless steel.

In some embodiments of the foregoing aspects, the conductive contactstrips comprise laser cladded Ni—Ti or Cu—Ti. In some embodiments of theforegoing aspects, the conductive contact strips comprise nickel lasercladded on titanium or copper laser cladded on titanium or vice versa.In some embodiments of the foregoing aspects and embodiment, theconductive contact strips comprise explosion bonded Ni—Ti or Cu—Ti. Insome embodiments of the foregoing aspects and embodiments, theconductive contact strips comprises titanium explosion bonded on nickelor nickel explosion bonded on titanium. In some embodiments of theforegoing aspects and embodiments, the U-shaped or the Z-shaped elementshave a flat apex. In some embodiments of the foregoing aspects andembodiments, the V-shaped, the U-shaped, or the Z-shaped elements have aflat base. In some embodiments of the foregoing aspects and embodiments,the cathode shell comprises vertical internal current bars and each ofthe bases of the V-shaped, the U-shaped, or the Z-shaped elements are inan alternate alignment with the vertical internal current bars in thecathode shell so that the current distribution is substantially uniformacross the one or more ion exchange membranes.

In some embodiments of the foregoing aspects and embodiments, theplurality of the V-shaped, the U-shaped, or the Z-shaped elements areindividual elements or form a sheet. In some embodiments of theforegoing aspects and embodiments, the plurality of the V-shaped, theU-shaped, or the Z-shaped elements provide substantially uniform currentdistribution. In some embodiments of the foregoing aspects andembodiments, the plurality of the V-shaped, the U-shaped, or theZ-shaped elements enable air flow to provide convective cooling orheating outside the anode shell.

In some embodiments of the foregoing aspects and embodiments, the anodecomprises a corrugated porous anode. In some embodiments of theforegoing aspects and embodiments, the apexes of the plurality of theV-shaped, the U-shaped, or the Z-shaped elements are perpendicular toamplitude of corrugation of the corrugated porous anode. In someembodiments of the foregoing aspects and embodiments, the apexes of theplurality of the V-shaped, the U-shaped, or the Z-shaped elements areparallel to amplitude of corrugation of the corrugated porous anode.

In some embodiments of the foregoing aspects and embodiments, the lengthbetween the apex and the base of the V-shaped, the U-shaped, or theZ-shaped element is between about 5-30 mm. In some embodiments of theforegoing aspects and embodiments, the distance between the apexes ofadjacent V-shaped, adjacent U-shaped, or adjacent Z-shaped elements isbetween about 5-200 mm. In some embodiments of the foregoing aspects andembodiments, the V-shaped, the U-shaped, or the Z-shaped elementsprovide a gap of between about 5-50 mm between the anode and the cathodeof two adjacent electrochemical cells stacked in the electrolyzer.

In one aspect, there is provided an electrolyzer comprising multiplicityof individual foregoing electrochemical cells.

In one aspect, there is provided an anode assembly, comprising an anodeshell; an anode positioned inside the anode shell; and a plurality ofV-shaped, U-shaped, or Z-shaped elements positioned outside the anodeshell and in electrical contact with the anode. In some embodiments ofthe foregoing aspect, each of the plurality of the V-shaped, theU-shaped, or the Z-shaped elements comprise an apex and a base; and theapexes comprise conductive contact strips; are coated with nickel,copper, or iron; cladded with nickel, copper, or iron; sprayed withnickel, copper, or iron; bonded with nickel, copper, or iron; orcombinations thereof. In some embodiments of the foregoing aspect andembodiments, the conductive contact strips comprise explosion bondedNi—Ti or laser cladded Ni—Ti.

In one aspect, there is provided a method comprising contacting an anodeshell and an anode positioned inside the anode shell, with a cathodeshell and a cathode positioned inside the cathode shell in anelectrochemical cell; and contacting a plurality of V-shaped, U-shaped,or Z-shaped elements to the outside of the anode shell such that theanode shell is in electrical contact with the plurality of V-shaped,U-shaped, or Z-shaped elements. In some embodiments of theaforementioned aspect, the method further comprises disposing one ormore ion exchange membranes between the anode shell and the cathodeshell.

In some embodiments of the foregoing aspect, each of the V-shaped, theU-shaped, or the Z-shaped elements comprises an apex and a base. In someembodiments of the foregoing aspect and embodiment, each of the V-shapedor the U-shaped elements comprises two legs of equal length meeting atthe apex. In some embodiments of the foregoing aspect and embodiment,each of the V-shaped or the U-shaped elements comprises two legs ofunequal length meeting at the apex.

In some embodiments of the foregoing aspect and embodiments, the methodfurther comprises metallurgically attaching each of the bases of theV-shaped, the U-shaped, or the Z-shaped elements to the outside of theanode shell thereby bringing it in electrical contact with the anode.

In some embodiments of the foregoing aspect and embodiments, the methodfurther comprises providing conductive contact strips on the apexes ofthe V-shaped, the U-shaped, or the Z-shaped elements; or coating,spraying, bonding, or cladding the apexes of the V-shaped, the U-shaped,or the Z-shaped elements with conductive metal e.g. nickel, copper, oriron such as an iron alloy. In some embodiments of the foregoing aspectand embodiments, the method further comprises laser cladding nickel orcopper on titanium or explosion bonding nickel or copper to titanium toform the conductive contact strips.

In some embodiments of the foregoing aspect and embodiments, the methodfurther comprises providing electrical continuity through the conductivecontact strips, between the anode shell of the electrochemical cell witha cathode shell of an adjacent electrochemical cell when theelectrochemical cells are stacked in an electrolyzer.

In some embodiments of the foregoing aspect and embodiments, the methodfurther comprises manufacturing the plurality of V-shaped, U-shaped, orZ-shaped elements by explosion bonding or laser cladding nickel andtitanium to form Ni—Ti sheets and configuring the Ni—Ti sheets to formthe plurality of V-shaped, U-shaped, or Z-shaped elements.

In some embodiments of the foregoing aspect and embodiments, the methodfurther comprises providing vertical internal current bars inside thecathode shell. In some embodiments of the foregoing aspect andembodiments, the method further comprises aligning each of the bases ofthe V-shaped, the U-shaped, or the Z-shaped elements in an alternatealignment with the vertical internal current bars and providingsubstantially uniform current distribution across the one or more ionexchange membranes. In some embodiments of the foregoing aspect andembodiments, providing substantially uniform current distribution in theelectrochemical cell through the plurality of the V-shaped, theU-shaped, or the Z-shaped elements.

In some embodiments of the foregoing aspect and embodiments, enablingair flow to provide convective cooling or heating outside the anodeshell through the plurality of the V-shaped, the U-shaped, or theZ-shaped elements.

In some embodiments of the foregoing aspect and embodiments, the anodecomprises a corrugated porous anode having amplitude of corrugation. Insome embodiments of the foregoing aspect and embodiments, the methodfurther comprises contacting the plurality of the V-shaped, theU-shaped, or the Z-shaped elements to the outside of the anode shellsuch that the apexes of the elements are perpendicular to the amplitudeof corrugation of the corrugated porous anode. In one aspect, there isprovided a method, comprising providing a V-shaped, U-shaped, orZ-shaped element, wherein the V-shaped, the U-shaped, or the Z-shapedelement comprises an apex and a base, and wherein the V-shaped,U-shaped, or Z-shaped element is made of titanium; and attaching a Ni—Tior Cu—Ti conductive contact strip to the apex of the V-shaped, U-shaped,or Z-shaped element; or coating, cladding, spraying, or bonding nickelor copper on titanium apex of the V-shaped, U-shaped, or Z-shapedelement. In some embodiments of the aforementioned aspect, there areprovided a plurality of the V-shaped, U-shaped, or Z-shaped elements.

In some embodiments of the aforementioned aspects and embodiments, thecoating comprises electroless or electrolytic coating process.

In some embodiments of the aforementioned aspects, the claddingcomprises laser cladding process. In some embodiments of theaforementioned aspect and embodiment, the method further comprisesdepositing Ni or Cu on the Ti apex of the V-shaped, U-shaped, orZ-shaped element in the laser cladding process to form a Ni—Ti or Cu—Ticonductive contact strip on the apex of the V-shaped, U-shaped, orZ-shaped element. In some embodiments of the aforementioned aspect andembodiment, the method further comprises milling the strip to flattensurface of the conductive contact strip. In some embodiments of theaforementioned aspect and embodiments, the depositing step is done whiledestroying or removing oxide layer from Ti apex. In some embodiments ofthe aforementioned aspect and embodiments, the depositing of Ni or Cucomprises depositing Ni or Cu powder or metal wire on the Ti apex. Insome embodiments, the powder or the metal wire further comprises aluminato destroy or remove oxide layer from Ti.

In some embodiments of the aforementioned aspect and embodiments, themethod further comprises destroying or removing oxide layer from the Tiapex before the laser cladding process by sand blasting, mechanicalabrasion, treatment with alumina, or acid pickling.

In some embodiments of the aforementioned aspect and embodiments, themethod further comprises keeping the Ti apex of the V-shaped, U-shaped,or Z-shaped element in inert atmosphere until subjecting the Ti apex tothe laser cladding process.

In some embodiments of the aforementioned aspect and embodiment, thespraying comprises an additive process such as but not limited to,chemical vapor deposition process (CVD) or cold spray deposition.

In some embodiments of the aforementioned aspect and embodiment, thebonding comprises explosion bonding process.

In one aspect, there is provided a process for manufacturing an anodeassembly, comprising attaching a plurality of V-shaped, U-shaped, orZ-shaped elements positioned outside an anode shell; and attaching ananode inside the anode shell.

In some embodiments of the foregoing aspects, the process comprisesmetallurgically attaching the anode to the inside of the anode shell.

In some embodiments of the foregoing aspects, the process comprisesmetallurgically attaching the plurality of the V-shaped, the U-shaped,or the Z-shaped elements outside the anode shell such that the pluralityof the V-shaped, the U-shaped, or the Z-shaped elements are inelectrical contact with the anode.

In some embodiments of the foregoing aspect and embodiments, each of theplurality of the V-shaped, the U-shaped, or the Z-shaped elementscomprise an apex and a base and each of the bases of the plurality ofthe V-shaped, the U-shaped, or the Z-shaped elements are attachedoutside the anode shell.

In some embodiments of the foregoing aspect and embodiments, the processfurther comprising providing conductive contact strips on the apexes ofthe V-shaped, the U-shaped, or the Z-shaped elements; or coating,bonding, spaying, or laser cladding the apexes of the V-shaped, theU-shaped, or the Z-shaped elements with nickel or copper, before orafter the attaching step.

In one aspect, there is provided a process for manufacturing anelectrochemical cell, comprising assembling an individualelectrochemical cell by joining together the anode assembly of any ofthe foregoing embodiments with a cathode assembly comprising a cathodeshell and a cathode; placing the anode assembly and the cathode assemblyin parallel and separating them by one or more ion exchange membranes;and supplying the electrochemical cell with feeders for a cell currentand an electrolysis feedstock. In some embodiments of the foregoingaspect, the process further comprises reciprocally fastening the anodeassembly, the cathode assembly, and the one or more ion exchangemembranes by peripheral bolting.

In one aspect, there is provided a process for assembling anelectrolyzer, comprising assembling foregoing individual electrochemicalcells; and placing a plurality of the assembled electrochemical cellsside by side in a stack and bracing them together so as to sustainelectrical contact between the electrochemical cells. In someembodiments of the foregoing aspects, the electrical contact between theanode shell of one electrochemical cell and the cathode shell of theadjacent electrochemical cell is through the conductive contact stripson the apexes of the V-shaped, the U-shaped, or the Z-shaped elementspositioned outside the anode shell; or through coated, laser cladded,sprayed, or explosion bonded nickel or copper on the apexes of theV-shaped, the U-shaped, or the Z-shaped elements.

In one aspect, there is provided a process for manufacture of Ni—Ti orCu—Ti conductive contact strip for electrochemical cell comprising:depositing Ni or Cu on surface of a Ti strip or depositing Ti on surfaceof a Ni or Cu strip by laser cladding process to obtain a Ni—Ti or Cu—Ticonductive contact strip for an electrochemical cell. In someembodiments of the aforementioned aspect, the process further comprisesproviding a longitudinal slot in a central part of the Ni—Ti or Cu—Ticonductive contact strip to form two strips of Ni or Cu and exposing aTi surface of the Ti strip. In some embodiments of the aforementionedaspect and embodiment, the process further comprises milling the stripto flatten surface of the conductive contact strip. In some embodimentsof the aforementioned aspect and embodiments, the depositing the Ni orCu comprises depositing Ni powder, Ni metal wire, Cu powder, or Cu metalwire or depositing the Ti comprises depositing Ti powder or Ti metalwire.

In some embodiments of the aforementioned aspect and embodiments, thedepositing Ni or Cu step is done while destroying or removing oxidelayer from Ti strip. In some embodiments of the aforementioned aspectand embodiments, the Ni or Cu powder or metal wire further comprisesalumina to destroy or remove oxide layer from Ti. In some embodiments ofthe aforementioned aspect and embodiments, the process further comprisesdestroying or removing oxide layer from the Ti surface of the Ti stripbefore the depositing Ni or Cu step by sand blasting, mechanicalabrasion, treatment with alumina, or acid pickling. In some embodimentsof the aforementioned aspect and embodiments, the process furthercomprises keeping the Ti strip in inert atmosphere until subjecting theTi strip to the laser cladding process. In some embodiments of theaforementioned aspect and embodiments, the process further comprisesattaching the Ni—Ti or Cu—Ti conductive contact strip to an anode shellof an electrochemical cell. In some embodiments of the aforementionedaspect and embodiments, the process further comprises attaching theNi—Ti or Cu—Ti conductive contact strip to an apex of a V-shaped,U-shaped, or Z-shaped element attached to the anode shell.

In one aspect, there is provided a method of establishing an electricalcontact between adjacent electrochemical cells in an electrolyzer, themethod comprising:

obtaining a Ni—Ti or Cu—Ti conductive contact strip by depositing Ni orCu on surface of a Ti strip or depositing Ti on surface of Ni or Custrip by laser cladding process to form Ni—Ti or Cu—Ti conductivecontact strip and providing a longitudinal slot in a central part of theNi—Ti or Cu—Ti conductive contact strip to form two strips of Ni or Cuand exposing a Ti surface of the Ti strip, thereby obtaining a Ni—Ti orCu—Ti conductive contact strip for the electrochemical cell; attachingthe Ni—Ti or Cu—Ti conductive contact strip to an anode shell of anelectrochemical cell by welding the exposed Ti surface of the Ti stripto the anode shell, wherein the anode shell is made of Ti; and

establishing an electrical contact between adjacent electrochemicalcells in the electrolyzer by contacting the anode shell of theelectrochemical cell with a cathode shell of an adjacent electrochemicalcell via the two strips of Ni or Cu in the Ni—Ti or Cu—Ti conductivecontact strip.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention may be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 illustrates some embodiments related to the electrochemical cell.

FIGS. 2A-2C are an illustration of some embodiments related to theplurality of the U-shaped elements and the anode shell attached to thesame.

FIGS. 3A and 3B illustrate some embodiments related to the V-shapedelements and the anode shell attached to the same.

FIGS. 4A and 4B illustrate some embodiments related to the U-shapedelements and the anode shell attached to the same.

FIGS. 5A and 5B illustrate some embodiments related to the Z-shapedelements and the anode shell attached to the same.

FIG. 6 illustrates some embodiments related to the V-shaped, theU-shaped, or the Z-shaped elements with the conductive contact strips;or bonded, coated, sprayed, or cladded conductive metal, such as, nickelor copper.

FIG. 7 illustrates some embodiments related to the anode assembly.

FIG. 8 illustrates some embodiments related to the electrochemical cellcontaining the anode assembly of the invention.

FIGS. 9A and 9B illustrate some embodiments related to the currentdistribution in the electrochemical cell with and without the anodeassembly of the invention.

FIGS. 10A and 10B illustrate experimental results as described inExample 1 herein.

DETAILED DESCRIPTION

Disclosed herein is an anode assembly, conductive contact strips,electrochemical cells comprising the anode assembly and the conductivecontact strips, and methods and processes of using, assembling, andmanufacturing the same.

Before the present invention is described in greater detail, it is to beunderstood that this invention is not limited to particular embodimentsdescribed, as such may, of course, vary. It is also to be understoodthat the terminology used herein is for the purpose of describingparticular embodiments only, and is not intended to be limiting, sincethe scope of the present invention will be limited only by the appendedclaims.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimit of that range and any other stated or intervening value in thatstated range, is encompassed within the invention. The upper and lowerlimits of these smaller ranges may independently be included in thesmaller ranges and are also encompassed within the invention, subject toany specifically excluded limit in the stated range. Where the statedrange includes one or both of the limits, ranges excluding either orboth of those included limits are also included in the invention.

Certain ranges that are presented herein with numerical values may beconstrued as “about” numericals. The “about” is to provide literalsupport for the exact number that it precedes, as well as a number thatis near to or approximately the number that the term precedes. Indetermining whether a number is near to or approximately a specificallyrecited number, the near or approximating unrequited number may be anumber, which, in the context in which it is presented, provides thesubstantial equivalent of the specifically recited number.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present invention, representativeillustrative methods and materials are now described.

All publications and patents cited in this specification are hereinincorporated by reference as if each individual publication or patentwere specifically and individually indicated to be incorporated byreference and are incorporated herein by reference to disclose anddescribe the methods and/or materials in connection with which thepublications are cited. The citation of any publication is for itsdisclosure prior to the filing date and should not be construed as anadmission that the present invention is not entitled to antedate suchpublication by virtue of prior invention. Further, the dates ofpublication provided may be different from the actual publication dateswhich may need to be independently confirmed.

It is noted that, as used herein and in the appended claims, thesingular forms “a,” “an,” and “the” include plural references unless thecontext clearly dictates otherwise. It is further noted that the claimsmay be drafted to exclude any optional element. As such, this statementis intended to serve as antecedent basis for use of such exclusiveterminology as “solely,” “only” and the like in connection with therecitation of claim elements, or use of a “negative” limitation.

As will be apparent to those of skill in the art upon reading thisdisclosure, each of the individual embodiments described and illustratedherein has discrete components and features which may be readilyseparated from or combined with the features of any of the other severalembodiments without departing from the scope or spirit of the presentinvention. Any recited method can be carried out in the order of eventsrecited or in any other order which is logically possible.

Anode Assembly, Conductive Contact Strips, Electrochemical Cells, andMethods

In a typical electrochemical cell, there is an anode chamber that housesan anode and an anode electrolyte. There is a cathode chamber thathouses a cathode and a cathode electrolyte and the anode chamber and thecathode chamber are separated by one or more ion exchange membranes(IEM). The IEM may be an anion exchange membrane (AEM), a cationexchange membrane (CEM), or both depending on the desired reactions atthe anode and the cathode. In between these components, variousadditional separator components may be provided to separate, e.g. theAEM from the anode, the CEM from the cathode and/or AEM from the CEM aswell as provide mechanical integrity to the membranes. In addition tothese components, individual gaskets or gasket tape may be provided inbetween and along the outer perimeter of the components to seal thecompartments from fluid leakage. In some electrolyzers, theelectrochemical system includes the anode and the cathode separated byboth the AEM and the CEM creating a third chamber in the middlecontaining the electrolyte.

In an illustrative embodiment, the electrochemical cell is shown inFIG. 1. As illustrated in FIG. 1, the cell houses an anode electrodeassembly and a cathode electrode assembly. The anode electrode assemblycomprises an anode shell and an anode therein. The cathode electrodeassembly comprises a cathode shell and a cathode therein. The twochambers are separated by the one or more ion exchange membranes such asthe AEM and/or the CEM disposed between the anode assembly and thecathode assembly. In embodiments where both the AEM and the CEM arepresent (not shown in FIG. 1), between the AEM and the CEM may be anintermediate frame that forms an intermediate chamber for feeding theelectrolyte in the cell. Gaskets may be present around the cell's activearea in order to form liquid seals. Separators, woven or unwoven, may bepresent to prevent the membranes from touching each other. Many suchcombinations are possible and are within the scope of the invention. Allthe components described above may be aligned parallel to each other andoptional peripheral bolting may be provided to stack them together inthe electrochemical cell. In filter press configuration, no peripheralbolting may be required. In a stack of electrochemical cells, the anodeof one electrochemical cell is in contact with the cathode of theadjacent electrochemical cell. The current passes through the stack ofelectrochemical cells during operation.

In a typical cell, a series of vertical support bars may be used tomount the anode across the anode shell. A second series of verticalsupport bars may be used to mount the cathode across the cathode shell.In addition to providing mechanical support for the electrodes, thesupports may also provide current path through the cell. The current maybe injected into the outer surface of the anode shell. It may then flowthrough the anode support bars. After passing through the anode, themembrane, and the cathode; the current may flow through the cathodesupports bars, and out the back surface of the cathode shell.

The voltage distribution and resultant current flow from anode currentbars/anode interface to cathode/cathode current bars interface mayimpact the performance and reliability of the electrochemical cells. Forexample, due to the vertical support bars, variable thickness gapsbetween the membrane and the two electrodes may get distributed acrossthe active area leading to the formation of pockets of the anolyteand/or the catholyte. Each pocket of the anolyte (catholyte) between theanode (cathode) and the membrane may comprise a resistance to currentflow. The net effect may be a concentration of current through thelow-resistance regions, and a reduction of current in thehigh-resistance regions (fluid pockets). The resultant non-uniformcurrent distribution may drive the overall cell voltage upward. Thisnon-uniform current distribution may also lead to regions of relativelyhigh current density which can damage membranes due to joule orresistance heating.

Provided herein is a unique anode assembly for the electrochemical cellthat enhances current distribution in the electrochemical cell andreduces or prevents harmful effects of current concentration such as,but not limited to, higher voltage, damage to membrane(s) in theelectrochemical cell, etc.

The anode assembly provided herein comprises a plurality of corrugatedelements attached to the outside of the anode shell which are inelectrical contact with the anode. The corrugated elements may be of anydesired shape, few of which have been described herein. In one aspect,there is a provided an anode shell comprising a plurality of V-shaped,U-shaped, Z-shaped elements or combinations thereof positioned outsidethe anode shell. The “V-shape, the U-shape, and the Z-shape” usedherein, are different geometries of the elements that are attached tothe outside of the shell. It is to be understood that variation of thesegeometries such as softened or rounded edges of the shapes such asinverted S-shape (same as Z-shape but softened edges) or slight U-shape(softened or rounded V-shape); sharpened edges such as U-shape withsharpened edges or corners instead of rounded edges; or other shapessimilar to the V-shape, U-shape, or Z-shape such as W-shape (same as twoV-shapes joined together), etc. are all within the scope of theinvention.

In some embodiments of this aspect, the anode shell further comprises ananode attached inside the anode shell where the plurality of theV-shaped, the U-shaped, the Z-shaped elements, or combinations thereofare in electrical contact with the anode. The attachment of theV-shaped, the U-shaped or the Z-shaped elements to the outside of theanode shell and the attachment of the anode to the inside of the anodeshell is such that the elements are in direct electrical contact withthe anode (described in detail herein). Accordingly, there is providedan anode assembly, comprising an anode shell; an anode positioned orattached inside the anode shell; and a plurality of V-shaped, U-shaped,Z-shaped elements, or combinations thereof positioned outside the anodeshell and in electrical contact with the anode.

An illustrative embodiment of an anode shell is provided in FIGS. 2A-C.An isometric view of the anode shell is illustrated in FIGS. 2A and 2B,where the U-shaped elements 1 are positioned on the outside of the anodeshell or a base sheet 2. There are manifolds 3 attached on either sideof the anode shell for anolyte or anode electrolyte to flow inside theanode shell in the anode chamber. Since the V-shaped, the U-shaped, orthe Z-shaped elements are outside the anode shell, no anolyte flowsthrough the elements. A side-view of the anode shell is illustrated inFIG. 2C. While the U-shaped elements are positioned outside the anodeshell, the anode is positioned inside the anode shell and is in contactwith the anode electrolyte (anode is not illustrated in FIGS. 2A-C).FIG. 2A illustrates an embodiment where the U-shaped elements areindividual elements. In some embodiments, the V-shaped, the U-shaped,and the Z-shaped elements are in a form of a sheet containing any numberof the V-shaped, the U-shaped, and the Z-shaped elements. In someembodiments, the V-shaped, the U-shaped, and the Z-shaped elements areindividual pieces of the elements. The V-shaped, the U-shaped, and theZ-shaped elements are illustrated in FIGS. 3A-B, FIGS. 4A-B, and FIGS.5A-B, respectively. The V-shaped, the U-shaped, and the Z-shapedelements are made from an electro conductive material such as, but notlimited to, titanium, titanium alloys, stainless steel, stainless steelalloys, inconel, hastelloy, and the like.

It is to be understood that FIGS. 3A-B, FIGS. 4A-B, and FIGS. 5A-B areillustrations of the geometries of the elements and are in no waylimiting to the thickness, proportion, or orientation of the elements.For example, FIGS. 2A-C illustrate five U-shaped elements attached tothe anode shell. However, any desired number of the individual V-shaped,the U-shaped, and the Z-shaped elements may be attached to the anodeshell or the sheet containing the elements may have any number of thedesired V-shaped or U-shaped or Z-shaped elements in it. Any other shaperesembling the V-shaped, the U-shaped, or the Z-shaped elements is wellwithin the scope of the invention. FIG. 3A illustrates a sheet of theV-shaped elements 1 while FIG. 3B illustrates a sheet of the V-shapedelements 1 attached to the anode shell 2. FIG. 4A illustrates a sheet ofthe U-shaped elements 1 while FIG. 4B illustrates a sheet of theU-shaped elements 1 attached to the anode shell 2. The U-shape isillustrated with a slightly expanded or stretched U-shape; however,other variations of the U shape including the one with a straight U (noexpansion or stretch) are well within the scope of the invention. FIG.5A illustrates the Z-shaped elements 1 while FIG. 5B illustrates theZ-shaped elements 1 attached to the anode shell 2. In some embodiments,the V-shaped, the U-shaped, or the Z-shaped elements may be attached toa separate sheet before attaching the sheet to the anode shell.

In some embodiments of the aspects and embodiments provided herein, eachof the V-shaped, the U-shaped, or the Z-shaped elements comprises anapex A and a base B, as illustrated in FIGS. 3A-B, FIGS. 4A-B, and FIGS.5A-B, respectively. In some embodiments of the aspects and embodimentsprovided herein, each of the V-shaped or the U-shaped elements comprisestwo legs meeting at the apex. The two legs may be symmetrical and haveequal lengths or the two legs may be unsymmetrical and may be of unequallengths. In some embodiments of the aspects and embodiments providedherein, each of the V-shaped or the U-shaped elements comprises two legsof equal length meeting at the apex. In some embodiments of the aspectsand embodiments provided herein, each of the V-shaped or the U-shapedelements comprises two legs of unequal length meeting at the apex. Insome embodiments of the aspects and embodiments provided herein, theU-shaped or the Z-shaped elements have a flat apex. It is to beunderstood that in some embodiments, the U-shaped element may not have aflat apex and is a curved U-shaped apex. In some embodiments, the apexesof the elements provide a site for attaching conductive contact stripsor coating, cladding, spraying, or bonding a conductive metal such as,but not limited to, nickel, copper, iron, etc. (described in detailfurther herein). In some embodiments of the aspects and embodimentsprovided herein, the V-shaped or the U-shaped or the Z-shaped elementshave a flat base. The V-shaped or the U-shaped or the Z-shaped elementsprovided herein, are attached to the anode shell using the flat base ofthe elements. In embodiments, where the V-shaped or the U-shaped or theZ-shaped elements are in a form of a sheet, the base of the elements isused to attach the sheet of the elements to the anode shell. In someembodiments of the aspects and embodiments provided herein, each of thebases of the V-shaped, the U-shaped, or the Z-shaped elements ismetallurgically attached to the outside of the anode shell bringing itin electrical contact with the anode. The “metallurgical” or grammaticalequivalent thereof, used herein includes any metallurgical technique toattach the elements or the anode to the anode shell. Examples of suchtechniques have been provided herein. In some embodiments of the aspectsand embodiments provided herein, each of the bases of the V-shaped, theU-shaped, or the Z-shaped elements is metallurgically attached to theoutside of the anode shell and the anode is metallurgically attached tothe inside of the anode shell thereby bringing the V-shaped, theU-shaped, or the Z-shaped elements in electrical contact with the anode.

While the V-shaped or the U-shaped or the Z-shaped elements can be ofany desired length and width, in some embodiments of the aspectsdescribed herein, the length (illustrated as C in FIGS. 3A-B, FIGS.4A-B, and FIGS. 5A-B) between the apex and the base of the V-shaped, theU-shaped, or the Z-shaped element is between about 5-30 mm. In someembodiments, the length between the apex and the base of the V-shaped,the U-shaped, or the Z-shaped element is between about 5-30 mm; orbetween about 5-25 mm; or between about 5-20 mm; or between about 5-15mm; or between about 5-10 mm; or between about 5-8 mm; or between about10-30 mm; or between about 10-25 mm; or between about 10-20 mm; orbetween about 10-15 mm; or between about 15-30 mm; or between about15-25 mm; or between about 15-20 mm; or between about 20-30 mm; orbetween about 20-25 mm. For example, in some embodiments, the lengthbetween the apex and the base of the V-shaped, the U-shaped, or theZ-shaped element is between about 10-30 mm, or between about 15-30 mm,or between about 20-30 mm.

In some embodiments of the aspects provided herein, the distance(illustrated as D in FIGS. 3A-B, FIGS. 4A-B, and FIGS. 5A-B) between theapexes of adjacent V-shaped, adjacent U-shaped, or adjacent Z-shapedelements is between about 5-200 mm or between about 30-150 mm. Inembodiments where the apex may be flat (e.g. in the U-shaped and theZ-shaped elements), the distance between the apexes is from the centerof the first apex to the center of the adjacent apex. In someembodiments, the distance between the apexes of the adjacent V-shaped,the adjacent U-shaped, or the adjacent Z-shaped element is between about5-200 mm; or between about 5-150 mm; or between about 5-100 mm; orbetween about 5-75 mm; or between about 5-50 mm; or between about 30-150mm; or between about 30-125 mm; or between about 30-100 mm; or betweenabout 30-75 mm; or between about 30-50 mm; or between about 50-150 mm;or between about 50-125 mm; or between about 50-100 mm; or between about50-75 mm; or between about 75-150 mm; or between about 75-125 mm; orbetween about 75-100 mm; or between about 100-150 mm; or between about100-125 mm; or between about 125-150 mm. For example, in someembodiments, the distance between the apexes of the adjacent V-shaped,the adjacent U-shaped, or the adjacent Z-shaped element is between about50-150 mm, or between about 75-150 mm, or between about 100-150 mm, orbetween about 125-150 mm, between about 50-75 mm, between about 50-100mm.

Each of the apexes of the V-shaped, the U-shaped, or the Z-shapedelements attached on the anode shell of the electrochemical cell canprovide region of electrical contact for the current to distribute tothe anode and further to the one or more ion exchange membranes and thecathode of the electrochemical cell. Each of the apexes of the V-shaped,the U-shaped, or the Z-shaped elements on the anode shell of theelectrochemical cell can also provide region of electrical contact forthe current distribution with the cathode shell of an adjacentelectrochemical cell when the electrochemical cells are stacked togetherin an electrolyzer containing multiplicity of individual electrochemicalcells.

In a typical operation, cells may be arranged anode-to-cathode in alarge linear array in the electrolyzer. If a low contact resistancepathway is not provided across the array, the ohmic losses (voltagegains) across the interfaces may be large. The anode and the cathodeshells are made of a conductive metal. The “conductive metal” as usedherein, includes any conductive metal suitable to be used as an anodeshell or the cathode shell. For example, in some embodiments, the anodeshell and the V-shaped, the U-shaped, or the Z-shaped elements are madeof a conductive metal such as, but not limited to, titanium, titaniumalloys, stainless steel, stainless steel alloys, inconel, hastelloy, andthe like and the cathode shell is made of a conductive metal such as,but not limited to, nickel (Ni), copper (Cu), iron (Fe), silver, gold,aluminum, brass/bronze, carbon, any platinum group metal, engineeredconductive plastics, or any alloy thereof.

Titanium (Ti) of the anode shell may rapidly form a tenacious,high-resistance oxide coating when exposed to air. The electricalcontact resistance between e.g. Ti of the anode side of oneelectrochemical cell with the Ni of the cathode side of anotherelectrochemical cell in an electrolyzer may be high. The electricalcontact resistance across e.g. a Ni—Ni or Cu—Ni mechanical contact maybe significantly less than the resistance across a Ti—Ni mechanicalinterface.

In some embodiments of the aspects and embodiments provided herein, theanode assembly design provided herein achieves the desired nickel-nickel(Ni—Ni) or iron-iron (Fe—Fe) or copper-copper (Cu—Cu) or copper-nickel(Cu—Ni) contact between the anodes (e.g. made of Ti), and the adjacentcathodes (e.g. made of Ni or Fe or Cu) in a linear array of theelectrochemical cells by using conductive contact strips of Ni—Ti,Cu—Ti, or Fe—Ti (with Ti interfacing towards the anode side and Cu, Ni,or Fe interfacing towards the cathode side). In some embodiments,instead of attaching the conductive contact strips on the apexes of theelements, the Ti apexes of the elements are coated with nickel, copper,or iron; or cladded with nickel, copper, or iron; or sprayed withnickel, copper, or iron; or bonded with nickel, copper, or iron.

The “conductive contact strip” as used herein includes strip of one ormore conductive metals. The conductive contact strip may be used tointerface anode shell of an electrochemical cell on one side and cathodeshell of an adjacent electrochemical cell on the other side therebyproviding electrical continuity between the electrochemical cells in anelectrolyzer. Few examples of the conductive metals are described above.In some embodiments of the aspects and embodiments provided herein, theapexes of the V-shaped, the U-shaped, or the Z-shaped elements compriseconductive contact strips; or are coated with nickel, copper, or iron;cladded with nickel, copper, or iron; sprayed with nickel, copper, oriron; or bonded with nickel, copper, or iron; or combinations thereof.The techniques for making conductive contact strips or the techniques ofcoating, cladding, spraying, or bonding have been provided herein.

In some embodiments of the aspects and embodiments provided herein, theconductive contact strips comprise explosion bonded or laser claddedNi—Ti, Fe—Ti, or Cu—Ti. The “Ni—Ti” or “Ti—Ni” used herein includesnickel-titanium layer. The “Cu—Ti” or “Ti—Cu” used herein includescopper-titanium layer. The “Fe—Ti” or “Ti—Fe” used herein includesiron-titanium layer. The “iron” or “Fe” as used herein includes iron oriron alloy such as, but not limited to, stainless steel. The conductivecontact strips may be any cathode metal sprayed, coated, bonded orcladded with anode metal to form two layers of metal in contact witheach other such as, e.g. Ni—Ti or Cu—Ti or iron-Ti or stainlesssteel-Ti, etc. In some embodiments, the cladding is laser cladding. Insome embodiments of the aspects and embodiments provided herein, theconductive contact strips provide electrical continuity between theanode shell of the electrochemical cell with a cathode shell of anadjacent electrochemical cell when the electrochemical cells are stackedin an electrolyzer.

In some embodiments of the aspects and embodiments provided herein, theapexes of the V-shaped, the U-shaped, or the Z-shaped elements aredirectly coated with nickel, copper or iron/iron alloy such as stainlesssteel. In some embodiments, the coating process is electroless wherenickel, copper, or iron/iron alloy such as stainless steel may be coatedon the apexes of the elements. In some embodiments, the coating processis electrolytic where nickel, copper, or iron/iron alloy such asstainless steel may be coated on the apexes of the elementselectrolytically.

In some embodiments of the aspects and embodiments provided herein, theapexes of the V-shaped, the U-shaped, or the Z-shaped elements aresprayed with nickel, copper or iron/iron alloy such as stainless steel.In some embodiments, the spraying process is an additive process suchas, but not limited to, chemical vapor deposition (CVD) or cold spraydeposition.

In some embodiments of the aspects and embodiments provided herein, theapexes of the V-shaped, the U-shaped, or the Z-shaped elements compriseconductive contact strips comprising laser cladded nickel, copper, oriron on titanium or each of the apexes are directly laser cladded withnickel, copper, or iron.

In some embodiments of the aspects and embodiments provided herein, theentire U, V or Z-shaped elements are directly made out of explosionbonded or laser cladded Ti—Ni, Fe—Ti or Cu—Ti sheet so that noconductive strips or coating with nickel or copper or iron is needed.

An illustration of the conductive contact strips (formed by claddingsuch as laser cladding or bonding such as explosion bonding); orcoating, bonding, cladding, or spraying of the apexes of the elementswith the conductive metal is shown in FIG. 6. As illustrated, the apexesof the V-shaped, the U-shaped, or the Z-shaped elements may be coated,bonded, cladded or sprayed with nickel or copper or iron (or any othermetal that the cathode shell is made of); or may have conductive contactstrips attached to the apexes of the elements, formed by explosionbonding or laser cladding of the titanium with nickel, copper, or iron.It is not necessary for all the apexes of all the V-shaped, theU-shaped, or the Z-shaped elements attached to the anode shell tocontain the conductive contact strips, or to be coated, bonded, cladded,or sprayed with the conductive metal. Sufficient number of apexes maycontain the conductive contact strips or are coated, bonded, cladded orsprayed with the conductive metal such that a uniform currentdistribution is established.

In some embodiments of the aspects and embodiments provided herein, theanode assembly comprises the anode shell; an anode positioned inside theanode shell; and the plurality of V-shaped, U-shaped, or Z-shapedelements positioned outside the anode shell and in electrical contactwith the anode, wherein the anode is a corrugated porous anode. In someembodiments of the aspects and embodiments provided herein the anode isa flat mesh anode and a corrugated porous anode. The anode shellcomprising the plurality of the V-shaped, the U-shaped, or the Z-shapedelements positioned outside the shell, as described in the foregoingaspects and embodiments, is then attached to the anode on the inside ofthe anode shell. An illustration of the alignment of the anode shellwith the anode is as illustrated in FIG. 7.

As illustrated in FIG. 7, the anode shell 2 containing the plurality ofthe V-shaped, the U-shaped, or the Z-shaped elements 1 is attached tothe anode 4 and/or 5. In some embodiments, the anode is a combination ofthe corrugated porous anode and a flat mesh anode. The corrugated porousanode and the flat mesh anode have been described in detail in U.S.patent application Ser. No. 13/799,131, filed Mar. 13, 2013, which isincorporated herein by reference in its entirety. The corrugated porousanode may have amplitude of corrugation between about 1 mm to 8 mm. Insome embodiments, the anode shell 2 containing the plurality of theV-shaped, the U-shaped, or the Z-shaped elements 1 on one side isstacked with the corrugated anode 4 on the other side, optionallyfurther stacked with a flat mesh anode 5 on top.

In some embodiments, the anode shell comprising the plurality of theV-shaped, the U-shaped, or the Z-shaped elements has the apexes of theV-shaped, the U-shaped, or the Z-shaped elements aligned parallel to theamplitude of corrugation of the corrugated porous anode. In someembodiments, the anode shell comprising the plurality of the V-shaped,the U-shaped, or the Z-shaped elements has the apexes of the V-shaped,the U-shaped, or the Z-shaped elements aligned perpendicular to theamplitude of corrugation of the corrugated porous anode. For example, asillustrated in FIG. 7, the apexes of the U-shaped elements 1 are alignedperpendicular to the amplitude of corrugation of the corrugated porousanode 4. The alignment of the apexes of the V-shaped, the U-shaped, orthe Z-shaped elements to the corrugated anode may be parallel orperpendicular so long as the amplitude of the corrugation of thecorrugated porous anode is perpendicular to the flow of the anolyte.

In one aspect, there is provided an electrochemical cell comprising oneor more combinations of the foregoing embodiments related to the anodeassembly. Accordingly, in one aspect, there is provided anelectrochemical cell comprising a cathode shell, a cathode positionedinside the cathode shell, an anode shell, an anode positioned inside theanode shell, and one or more ion exchange membranes, wherein the one ormore ion exchange membranes are disposed between the anode shell and thecathode shell; and a plurality of V-shaped, U-shaped, or Z-shapedelements positioned outside the anode shell and in electrical contactwith the anode. In one aspect, there is provided an electrochemicalcell, comprising a cathode shell, a cathode positioned inside thecathode shell, an anode shell, an anode positioned inside the anodeshell, and one or more ion exchange membranes, wherein the one or moreion exchange membranes are disposed between the anode shell and thecathode shell; and a plurality of V-shaped, U-shaped, or Z-shapedelements positioned outside the anode shell, wherein each of theV-shaped, the U-shaped, or the Z-shaped elements comprises an apex and abase, and wherein the apexes of the V-shaped, the U-shaped, or theZ-shaped elements comprise conductive contact strips, or wherein theapexes of the V-shaped, the U-shaped, or the Z-shaped elements arecoated, bonded, sprayed, or cladded with a conductive metal. One or moreof the foregoing aspects and embodiments related to the plurality ofV-shaped, U-shaped, or Z-shaped elements (including dimensions and othercharacteristics), and/or the conductive contact strips may be combinedto provide the electrochemical cells. It is to be understood that acombination of the V-shaped, the U-shaped, or the Z-shaped elements maybe attached to the anode shell if desired.

The anode assembly provided herein, comprising the anode shell and theplurality of the V-shaped, the U-shaped, or the Z-shaped elementsoutside the anode shell and further comprising the anode positionedinside the anode shell, is further stacked with other components of theelectrochemical cell. An illustrative example is shown in FIG. 1. It isto be understood that while FIG. 1 illustrates the electrochemical cellwhere the components are reciprocally fastened by peripheral bolting,other electrochemical cells without the peripheral bolting, such as, butnot limited to, filter press configurations are well within the scope ofthe invention. Various spacers and gaskets are provided in between thecomponents to prevent the components from being damaged, as explainedbefore. The membranes such as AEM and/or CEM are placed between theanode and the cathode. An AEM with a built-in separator has beendescribed in detail in U.S. application Ser. No. 15/071,648, filed Mar.16, 2016, which is incorporated herein by reference in its entirety. Theintermediate frame may be placed between the anode assembly and thecathode assembly and in between the AEM and the CEM to provide anintermediate chamber for entry and exit of the electrolyte. Anintermediate frame has been described in detail in U.S. patentapplication Ser. No. 15/498,341, filed Apr. 26, 2017, which isincorporated herein by reference in its entirety.

Typically, the commercially available cathode assembly comprises acathode shell attached to the cathode and vertical internal current barsthat connect the cathode shell/pan with the cathode. FIG. 8 illustratesan electrochemical cell containing the anode assembly of the inventioncompressed with the cathode assembly comprising the vertical currentbars inside the cathode shell.

As described before, the typical anode assembly comprises an anode shellattached to the anode and vertical internal current bars (or supportbars) that connect the anode shell/pan with the anode. The verticalcurrent bars in the anode shell are aligned with the vertical currentbars (or support bars) in the cathode shell in the electrochemical cellto provide a path of least current resistance. The current enters thecell through the anode side and flows from the vertical current bars inthe anode assembly to the vertical current bars in the cathode assemblythrough the cell's full active area. This is illustrated in FIG. 9Bwhere the dashed arrows represent the current pathway going from thevertical current bars in the anode assembly through the vertical currentbars in the cathode assembly. The current exits the cell through thevertical internal current bars in the cathode shell. However, thiscurrent pathway may not result in a spread of the current and may resultin the local thermal degradation of the components of the cell such as,the AEM (high current density may drive high power dissipation, whichmay lead to relatively high local temperatures). It has been explainedin Example 1 herein. However, the plurality of the V-shaped, theU-shaped, or the Z-shaped elements attached to the anode shell helpdistribute the current flow from the anode side by providing severalcurrent injection sites on the apexes of the elements through theconductive contact strips; or coating, spraying, bonding, or cladding ofthe conductive metal. In some embodiments of the aspects and embodimentsprovided herein, the each of the bases of the V-shaped, the U-shaped, orthe Z-shaped elements are in an alternate alignment with the verticalinternal current bars in the cathode shell so that the currentdistribution is substantially uniform across the one or more ionexchange membranes. As illustrated in FIG. 9A where the dashed arrowsrepresent the current pathway, the relatively long lateral current paththrough the plurality of the V-shaped, the U-shaped, or the Z-shapedelements, the corrugated anode and the vertical current bars of thecathode, results in a substantially uniform current density across theactive area of the cell. The substantially uniform current densityreduces or prevents localized high current density and localized hightemperatures resulting in reduction or prevention of damage to themembrane and other components of the cell.

In one aspect, there is provided an electrolyzer comprising multiplicityof individual electrochemical cells provided herein. In theelectrolyzer, the electrochemical cells are stacked together so that theanode assembly of one electrochemical cell is adjacent to the cathodeassembly of the adjacent electrochemical cell. As described before, theattaching of the conductive contact strips of Ni—Ti or Cu—Ti or Fe—Ti(as described above); or the coating, spraying, bonding, or cladding ofthe conductive metal such as nickel or copper, on the apexes of theelements attached to the anode shell provide current continuity by beingin electrical contact with the cathode shell (e.g. made of nickel orcopper) of the adjacent electrochemical cell. In some embodiments, theplurality of the V-shaped, the U-shaped, or the Z-shaped elements enableair flow between the cells to provide convective cooling or heatingoutside the anode shell. In some embodiments, the V-shaped, theU-shaped, or the Z-shaped elements provide a gap of between about 5-50mm or between about 5-30 mm between the anode and the cathode of twoadjacent electrochemical cells stacked in the electrolyzer. The gapbetween the anode and the cathode of two adjacent electrochemical cellsstacked in the electrolyzer is provided by the length of the V-shaped,the U-shaped, or the Z-shaped elements (length has been describedherein).

In the foregoing aspects, in some embodiments, the anode is configuredto oxidize the metal ions from a lower oxidation state to a higheroxidations state. For example, in some embodiments, the anode isconfigured to oxidize copper ions from Cu(I)Cl to Cu(II)Cl₂. Examples ofthe other metal ions include, without limitation, copper ions, platinumions, tin ions, chromium ions, iron ions etc. The metal ions may bepresent as a metal halide or a metal sulfate.

The electrochemical cell provided herein may be any electrochemical cellthat uses the anode assembly of the invention. The reactions in theelectrochemical cell using the components of the invention may be anyreaction carried out in the electrochemical cell including but notlimited to chloralkali processes. In some embodiments, theelectrochemical cell has an anode electrolyte containing metal ions andthe anode oxidizes the metal ions from the lower oxidation state to thehigher oxidation state in the anode chamber. Such electrochemical cellshave been described in detail in U.S. Patent Application Publication No.2012/0292196, filed May 17, 2012, issued as U.S. Pat. No. 9,187,834,issued Nov. 17, 2015, which is incorporated herein by reference in itsentirety. It is to be understood that the plurality of the U-shaped, theV-shaped, or the Z-shaped elements are outside the anode shell andtherefore, do not come in contact with the anode electrolyte. The anodeelectrolyte flows through the anode, e.g. through corrugated porousanode and flat mesh anode.

In the electrochemical cells provided herein, the cathode reaction maybe any reaction that does or does not form an alkali in the cathodechamber. Such cathode consumes electrons and carries out any reactionincluding, but not limited to, the reaction of water to form hydroxideions and hydrogen gas; or reaction of oxygen gas and water to formhydroxide ions (e.g. gas diffusion or oxygen depolarizing cathode); orreduction of protons from an acid such as hydrochloric acid to formhydrogen gas; or reaction of protons from hydrochloric acid and oxygengas to form water. In some embodiments, the electrochemical cells mayinclude production of alkali in the cathode chamber of the cell.

The electrochemical cells in the methods and systems provided herein aremembrane electrolyzers. The electrochemical cell may be a single cell ormay be a stack of cells connected in series or in parallel. Theelectrochemical cell may be a stack of 5 or 6 or 50 or 100 or moreelectrolyzers connected in series or in parallel. In some embodiments,the electrolyzers provided herein are monopolar electrolyzers. In themonopolar electrolyzers, the electrodes may be connected in parallelwhere all anodes and all cathodes are connected in parallel. In suchmonopolar electrolyzers, the operation takes place at high amperage andlow voltage. In some embodiments, the electrolyzers provided herein arebipolar electrolyzers. In the bipolar electrolyzers, the electrodes maybe connected in series where all anodes and all cathodes are connectedin series. In such bipolar electrolyzers, the operation takes place atlow amperage and high voltage. In some embodiments, the electrolyzersare a combination of monopolar and bipolar electrolyzers and may becalled hybrid electrolyzers.

In some embodiments of the bipolar electrolyzers as described above, thecells are stacked serially constituting the overall electrolyzer and areelectrically connected in two ways. In bipolar electrolyzers, a singleplate, called bipolar plate, may serve as base plate for both thecathode and anode. The electrolyte solution may be hydraulicallyconnected through common manifolds and collectors internal to the cellstack. The stack may be compressed externally to seal all frames andplates against each other, which are typically referred to as a filterpress design. In some embodiments, the bipolar electrolyzer may also bedesigned as a series of cells, individually sealed, and electricallyconnected through back-to-back contact, typically known as a singleelement design. The single element design may also be connected inparallel in which case it would be a monopolar electrolyzer.

In some embodiments, the anode used in the electrochemical systems maycontain a corrosion stable base support. Other examples of basematerials include, but not limited to, sub-stoichiometric titaniumoxides, such as, Magneli phase sub-stoichiometric titanium oxides havingthe formula TiO_(x) wherein x ranges from about 1.67 to about 1.9. Someexamples of titanium sub-oxides include, without limitation, titaniumoxide Ti₄O₇. The base materials also include, without limitation, metaltitanates such as M_(x)Ti_(y)O_(z) such as M_(x)Ti₄O₇, etc.

In some embodiments, the anode is not coated with an electrocatalyst. Insome embodiments, the electrodes described herein (including anodeand/or cathode) contain an electrocatalyst for aiding in electrochemicaldissociation, e.g. reduction of oxygen at the cathode or the oxidationof the metal ion at the anode. Examples of electrocatalysts include, butnot limited to, highly dispersed metals or alloys of the platinum groupmetals, such as platinum, palladium, ruthenium, rhodium, iridium, ortheir combinations such as platinum-rhodium, platinum-ruthenium,titanium mesh coated with PtIr mixed metal oxide or titanium coated withgalvanized platinum; electrocatalytic metal oxides, such as, but notlimited to, IrO₂; silver, gold, tantalum, carbon, graphite,organometallic macrocyclic compounds, and other electrocatalysts wellknown in the art for electrochemical reduction of oxygen or oxidation ofmetal.

In some embodiments, the electrodes described herein, relate to poroushomogeneous composite structures as well as heterogeneous, layered typecomposite structures wherein each layer may have a distinct physical andcompositional make-up, e.g. porosity and electroconductive base toprevent flooding, and loss of the three phase interface, and resultingelectrode performance.

Any of the cathodes provided herein can be used in combination with anyof the anodes described above. In some embodiments, the cathode used inthe electrochemical systems of the invention, is a hydrogen gasproducing cathode. In some embodiments, the cathode used in theelectrochemical systems of the invention, is a hydrogen gas producingcathode that does not form an alkali. The hydrogen gas may be vented outor captured and stored for commercial purposes. In some embodiments, thecathode in the electrochemical systems of the invention may be agas-diffusion cathode. In some embodiments, the gas-diffusion cathode,as used herein, is an oxygen depolarized cathode (ODC). The oxygen atthe cathode may be atmospheric air or any commercial available source ofoxygen. In some embodiments, the cathode in the electrochemical systemsof the invention may be a gas-diffusion cathode that reacts HCl andoxygen gas to form water. The oxygen at the cathode may be atmosphericair or any commercial available source of oxygen.

In some embodiments, the electrolyte in the electrochemical systems andmethods described herein include the aqueous medium containing more than1 wt % water. In some embodiments, the aqueous medium includes more than1 wt % water; more than 5 wt % water; or more than 5.5 wt % water; ormore than 6 wt %; or more than 20 wt % water; or more than 25 wt %water. In some embodiments, the aqueous medium may comprise an organicsolvent such as, e.g. water soluble organic solvent.

In some embodiments of the methods and systems described herein, theamount of total metal ion in the anode electrolyte in theelectrochemical cell or the amount of copper in the anode electrolyte orthe amount of iron in the anode electrolyte or the amount of chromium inthe anode electrolyte or the amount of tin in the anode electrolyte orthe amount of platinum is between 1-12M; or between 1-11M; or between1-10M; or between 1-9M; or between 1-8M; or between 1-7M; or between1-6M; or between 1-5M; or between 1-4M; or between 1-3M; or between1-2M. In some embodiments, the amount of total ion in the anodeelectrolyte, as described above, is the amount of the metal ion in thelower oxidation state plus the amount of the metal ion in the higheroxidation state; or the total amount of the metal ion in the higheroxidation state; or the total amount of the metal ion in the loweroxidation state.

In some embodiments of the methods and systems described herein, theanode electrolyte in the electrochemical systems and methods providedherein contains the metal ion and the alkali metal ion such as an alkalimetal halide. In some embodiments of the methods and systems describedherein, the anode electrolyte in the electrochemical systems and methodsprovided herein contains the metal ion in the higher oxidation state inthe range of 4-7M, the metal ion in the lower oxidation state in therange of 0.1-2M and the electrolyte in the intermediate chamber e.g.alkali metal halide such as sodium chloride in the range of 1-3M. Theanode electrolyte may optionally contain 0.01-0.1M hydrochloric acid. Insome embodiments of the methods and systems described herein, the anodeelectrolyte may contain another cation in addition to the metal ion.Other cation includes, but is not limited to, alkaline metal ions and/oralkaline earth metal ions, such as but not limited to, lithium, sodium,calcium, magnesium, etc. The amount of the other cation added to theanode electrolyte may be between 0.01-5M; or between 0.01-1M; or between0.05-1M; or between 0.5-2M; or between 1-5M.

In some embodiments, the aqueous electrolyte including the catholyte orthe cathode electrolyte and/or the anolyte or the anode electrolyte, orthe electrolyte introduced into the intermediate frame disposed betweenthe AEM and the CEM, in the systems and methods provided herein include,but not limited to, saltwater or fresh water. The saltwater includes,but is not limited to, seawater, brine, and/or brackish water. Saltwateris employed in its conventional sense to refer to a number of differenttypes of aqueous fluids other than fresh water, where the saltwaterincludes, but is not limited to, brine as well as other salines having asalinity that is greater than that of freshwater. Brine is watersaturated or nearly saturated with salt and has a salinity that is 50ppt (parts per thousand) or greater.

In some embodiments, the electrolyte including the cathode electrolyteand/or the anode electrolyte and/or the electrolyte introduced into theintermediate frame, such as, saltwater include water containing morethan 1% chloride content, e.g. alkali metal halides including sodiumhalide, potassium halide etc. e.g. more than 1% NaCl; or more than 10%NaCl; or more than 50% NaCl; or more than 70% NaCl; or between 1-99%NaCl; or between 1-70% NaCl; or between 1-50% NaCl; or between 1-10%NaCl; or between 10-99% NaCl; or between 10-50% NaCl; or between 20-99%NaCl; or between 20-50% NaCl; or between 30-99% NaCl; or between 30-50%NaCl; or between 40-99% NaCl; or between 40-50% NaCl; or between 50-90%NaCl; or between 60-99% NaCl; or between 70-99% NaCl; or between 80-99%NaCl; or between 90-99% NaCl; or between 90-95% NaCl. In someembodiments, the above recited percentages apply to ammonium chloride,ferric chloride, potassium chloride, sodium bromide, potassium bromide,sodium iodide, potassium iodide, sodium sulfate, or potassium sulfate asan electrolyte. The percentages recited herein include wt % or wt/wt %or wt/v %. It is to be understood that all the electrochemical systemsdescribed herein that contain sodium chloride can be replaced with othersuitable electrolytes, such as, but not limited to, ammonium chloride,sodium bromide, sodium iodide, sodium sulfate, potassium salts, orcombination thereof.

As used herein, the voltage includes a voltage or a bias applied to ordrawn from an electrochemical cell that drives a desired reactionbetween the anode and the cathode in the electrochemical cell. In someembodiments, the desired reaction may be the electron transfer betweenthe anode and the cathode such that an alkaline solution, water, orhydrogen gas is formed in the cathode electrolyte and the metal ion isoxidized at the anode. In some embodiments, the desired reaction may bethe electron transfer between the anode and the cathode such that themetal ion in the higher oxidation state is formed in the anodeelectrolyte from the metal ion in the lower oxidation state. The voltagemay be applied to the electrochemical cell by any means for applying thecurrent across the anode and the cathode of the electrochemical cell.Such means are well known in the art and include, without limitation,devices, such as, electrical power source, fuel cell, device powered bysun light, device powered by wind, and combinations thereof. The type ofelectrical power source to provide the current can be any power sourceknown to one skilled in the art. For example, in some embodiments, thevoltage may be applied by connecting the anodes and the cathodes of thecell to an external direct current (DC) power source. The power sourcecan be an alternating current (AC) rectified into DC. The DC powersource may have an adjustable voltage and current to apply a requisiteamount of the voltage to the electrochemical cell.

In some aspects, there are provided methods to make, manufacture, anduse the anode shell or the anode assembly, the conductive contactstrips, and/or the electrochemical cells containing the anode shell orthe anode assembly or the conductive contact strips provided herein.

In some aspects, there are provided methods to manufacture Ni—Ti orCu—Ti conductive contact strip for the electrochemical cell; and attachconductive contact strip to the apex of the V-shaped, U-shaped, orZ-shaped element, provided herein. In some embodiments, the conductivecontact strips are attached metallurgically to the elements. In someaspects, there are provided methods to coat, clad, spray, or bond nickelor copper on titanium apex of the V-shaped, U-shaped, or Z-shapedelement. The Ni or Cu may be substituted with any suitable conductivemetal compatible with the metal of the cathode shell.

In one aspect, there is provided a method comprising contacting an anodeshell and an anode positioned inside the anode shell with a cathodeshell and a cathode positioned inside the cathode shell in anelectrochemical cell; and contacting a plurality of V-shaped, U-shaped,or Z-shaped elements to the outside of the anode shell such that theanode shell is in electrical contact with the plurality of V-shaped,U-shaped, or Z-shaped elements. In some embodiments, the aforementionedmethod further comprises disposing one or more ion exchange membranesbetween the anode shell and the cathode shell.

Various embodiments related to the geometry, positioning, dimensions,material of construction, etc. related to the anode shell, the V-shaped,U-shaped, or Z-shaped elements, and the anode assembly containing thesame have been provided herein. In some embodiments of the foregoingaspect, each of the V-shaped, the U-shaped, or the Z-shaped elementscomprises an apex and a base. In some embodiments of the foregoingaspect and embodiments, each of the V-shaped or the U-shaped elementscomprises two legs of equal or unequal length meeting at the apex. Theapex and the base of the V-shaped, the U-shaped, or the Z-shapedelements have been described herein.

In some embodiments of the foregoing aspect and embodiments, the methodcomprises metallurgically attaching each of the bases of the V-shaped,the U-shaped, or the Z-shaped elements to the outside of the anode shellthereby bringing it in electrical contact with the anode. In someembodiments of the foregoing aspect and embodiments, the methodcomprises metallurgically attaching each of the bases of the V-shaped,the U-shaped, or the Z-shaped elements to the outside of the anode shelland metallurgically attaching the anode to the inside of the anode shellthereby bringing the V-shaped, the U-shaped, or the Z-shaped elements inelectrical contact with the anode. Various commercially availabletechniques for metallurgically attaching the V-shaped, the U-shaped, orthe Z-shaped elements to the anode shell and/or for metallurgicallyattaching the V-shaped, the U-shaped, or the Z-shaped elements to theoutside of the anode shell as well as the anode to the inside of theanode shell are well known to the one skilled in the art. Suchtechniques include, without limitation, diffusion bonding, soldering,welding, cladding e.g. laser cladding, brazing, and the like.

In some embodiments of the foregoing aspect and embodiments, the methodfurther comprises providing conductive contact strips on the apexes ofthe V-shaped, the U-shaped, or the Z-shaped elements. In someembodiments, the conductive contact strips may be metallurgicallyattached to the apexes of the V-shaped, the U-shaped, or the Z-shapedelements through the exposed Ti surface of the conductive contact strip(as explained herein and illustrated in FIG. 6).

In some embodiments of the foregoing aspect and embodiments, theconductive contact strips are formed by laser cladding or explosionbonding process. In some embodiments of the foregoing aspect andembodiments, the method comprises laser cladding nickel or copper ontitanium or titanium on nickel or copper; or explosion bonding nickel orcopper to titanium or titanium to nickel or copper, to form theconductive contact strips.

The conductive contact strips on the anode shell provide a point ofelectrical contact to induce current in the cell as well as provide aregion of electrical contact between the anode shell of one cell withthe cathode shell of the adjacent cell when the cells are stackedtogether in the electrolyzer. The conductive contact strips are madefrom two conductive metals, one compatible with the conductive metal ofthe anode shell (e.g. titanium) and one compatible with the conductivemetal of the cathode shell (e.g. nickel, copper, iron such as stainlesssteel or its alloys, silver, gold, aluminum, brass/bronze, carbon, anyplatinum group metal, or engineered conductive plastics, etc. or alloysthereof).

For example, the conductive contact strips of Ni—Ti can be formed in theexplosion bonding process by taking two large sheets of titanium andnickel. The sheets may be cleaned, loaded with blasting powder, andplaced in a cave. A controlled explosion may strip contaminants off ofthe two contacting surfaces, and cause the two materials to weldtogether. The plates may be cleaned, flattened and machined after theexplosion welding process. A longitudinal slot may be milled through thenickel portion of the strip. The strips may be laser welded to theoutside of the apexes of the elements (made from titanium; attached tothe titanium anode shell) along those longitudinal slots (also shown inFIG. 6). The removal of nickel to expose titanium in the slot preventsthe molten nickel and titanium metals from mixing. The conductivecontact strips thus formed comprise Ti—Ti weld, and two external Nistrips available for contacting the adjacent Ni cathode shell(illustrated in FIG. 6 or 8).

In some embodiments of the foregoing aspect and embodiments, theconductive contact strips are formed by laser cladding Ni—Ti.

In one aspect, there is provided a method, comprising providingV-shaped, U-shaped, or Z-shaped element, wherein the V-shaped, theU-shaped, or the Z-shaped element comprises an apex and a base, andwherein the V-shaped, U-shaped, or Z-shaped element is made of titanium;and attaching a Ni—Ti or Cu—Ti conductive contact strip to the apex ofthe V-shaped, U-shaped, or Z-shaped element; or coating, cladding,spraying, or bonding nickel or copper on titanium on the apex of theV-shaped, U-shaped, or Z-shaped element.

In one aspect, there is provided a method to form conductive contactstrips for an anode assembly, comprising: laser cladding nickel orcopper on titanium or titanium on nickel or copper to form conductivecontact strips of Ni—Ti or Cu—Ti and attaching the conductive contactstrips on an anode shell or attaching the conductive contact strips onthe apexes of the plurality of V-shaped, U-shaped, or Z-shaped elementsattached to the anode shell.

In one aspect, there is provided a process to manufacture Ni—Ti or Cu—Ticonductive contact strip for electrochemical cell comprising: depositingNi or Cu on surface of a Ti strip or depositing Ti on surface of a Ni orCu strip by laser cladding process to obtain a Ni—Ti or Cu—Ti conductivecontact strip for an electrochemical cell. In some embodiments of theaforementioned aspects, the method or the process further comprisesproviding a longitudinal slot (e.g. illustrated in FIG. 6) in a centralpart of the Ni—Ti or Cu—Ti conductive contact strip to form two stripsof Ni or Cu and exposing a Ti surface of the Ti strip (also illustratedin FIG. 6). In some embodiments, the aforementioned process furthercomprises attaching the Ni—Ti or Cu—Ti conductive contact strip to ananode shell of an electrochemical cell. In some embodiments, the processfurther comprises attaching the Ni—Ti or Cu—Ti conductive contact stripto an apex of a V-shaped, U-shaped, or Z-shaped element attached to theanode shell.

In one aspect, there is provided a method of establishing electricalcontact between adjacent electrochemical cells in an electrolyzer, themethod comprising:

obtaining a Ni—Ti or Cu—Ti conductive contact strip by depositing Ni orCu on surface of a Ti strip or depositing Ti on surface of Ni or Custrip by laser cladding process to obtain a Ni—Ti or Cu—Ti conductivecontact strip and providing a longitudinal slot in a central part of theNi—Ti or Cu—Ti conductive contact strip to form two strips of Ni or Cuand exposing a Ti surface of the Ti strip, thereby obtaining a Ni—Ti orCu—Ti conductive contact strip for the electrochemical cell;

attaching the Ni—Ti or Cu—Ti conductive contact strip to an anode shellof the electrochemical cell by welding the exposed Ti surface of the Tistrip to the anode shell, wherein the anode shell is made of Ti; and

establishing an electrical contact between adjacent electrochemicalcells in the electrolyzer by contacting the anode shell of theelectrochemical cell with a cathode shell of an adjacent electrochemicalcell via the two strips of Ni or Cu in the Ni—Ti or Cu—Ti conductivecontact strip.

In some embodiments, there is provided a method of establishingelectrical contact between adjacent electrochemical cells in anelectrolyzer, the method comprising:

obtaining a Ni—Ti or Cu—Ti conductive contact strip by depositing Ni orCu on surface of a Ti strip or depositing Ti on surface of Ni or Custrip by laser cladding process to obtain a Ni—Ti or Cu—Ti conductivecontact strip and providing a longitudinal slot in a central part of theNi—Ti or Cu—Ti conductive contact strip to form two strips of Ni or Cuand exposing a Ti surface of the Ti strip, thereby obtaining a Ni—Ti orCu—Ti conductive contact strip for the electrochemical cell;

attaching the Ni—Ti or Cu—Ti conductive contact strip to plurality ofV-shaped, U-shaped, or Z-shaped elements positioned outside an anodeshell by welding the exposed Ti surface of the Ti strip to apexes of theplurality of the V-shaped, U-shaped, or Z-shaped elements, wherein theV-shaped, U-shaped, or Z-shaped elements are made of Ti; and

establishing an electrical contact between adjacent electrochemicalcells in the electrolyzer by contacting the anode shell of theelectrochemical cell with a cathode shell of an adjacent electrochemicalcell via the two strips of Ni or Cu in the Ni—Ti or Cu—Ti conductivecontact strip.

In some embodiments of the aforementioned aspects and embodiments, thedepositing the Ni or Cu comprises depositing Ni powder, Ni metal wire,Cu powder, or Cu metal wire or depositing the Ti comprises depositing Tipowder or Ti metal wire. In some embodiments, the process furthercomprises milling the strip before or after providing the longitudinalslot to flatten surface of the conductive contact strip. In someembodiments, the depositing of Ni or Cu step is done while destroying orremoving oxide layer from Ti strip.

As explained above, the Ti of the anode shell or of the elementsprovided herein may rapidly form a tenacious, high-resistance oxidecoating when exposed to air. This coating may need to be destroyed orremoved before Ni, Cu, or Fe layer is deposited or coated or cladded orsprayed on the Ti surface of the strip or on the Ti apexes of theelements. In some embodiments of the aspects and embodiments providedherein, the laser cladding or the explosion bonding process to formconductive contact strips, or the coating, bonding, cladding or sprayingprocess on the apexes of the elements as described above, may be donewhile or after destroying or removing oxide layer from Ti surface. Insome embodiments, the oxide layer can be destroyed or removed from theTi surface of the Ti strip before or while the coating, cladding,bonding, or the spraying process by sand blasting, mechanical abrasion,treatment with alumina, or acid pickling.

In some embodiments, during the laser cladding process, the Ni or Cupowder or metal wire used may also contain particles of alumina whichmay remove the coating of the oxide layer from the Ti surface during thelaser cladding process while cladding a layer of Ni or Cu on the Tisurface (thereby obviating an additional step of oxide layer removal).In the acid pickling process, the anode shell or the elements providedherein may be put in acid solution (e.g. nitric acid or hydrofluoricacid) at high temperature to remove oxide layer.

After the removal of the oxide layer, the anode shell or the elementsmay need to be kept in inert atmosphere until the Ni or Cu is applied tothe Ti surface using any of the methods described herein.

In some embodiments, the Ni or Cu powder or metal wire further comprisesalumina to destroy or remove oxide layer from Ti. In some embodiments,the process further comprises destroying or removing oxide layer fromthe Ti surface of the Ti strip before the laser cladding process by sandblasting, mechanical abrasion, treatment with alumina, or acid pickling.In some embodiments, the process further comprises keeping the Ti stripin inert atmosphere until subjecting the Ti strip to the laser claddingprocess.

Laser cladding is an additive process that involves the deposition of amolten metal (e.g. Ni or Cu or any other conductive metal describedherein) onto another target metal (e.g. Ti) surface. The laser claddingprocess is a hard coating technique in which a cladding material withthe desired properties is fused onto a metal substrate by means of alaser beam, resulting in a metallurgical bond between the claddingmaterial and the metal substrate. Laser cladding can yield a claddinglayer that can have superior properties in terms of pureness,homogeneity, hardness, bonding and microstructure, as compared to otherhard coating techniques. The laser beam can be controlled to providefocused heating and localized melting of the substrate (e.g. titanium)and the cladding material (e.g. nickel or copper). Compared toconventional welding, laser cladding can provide minimal dilution and asmall heat affected zone where the substrate and the cladding materialmelt and minimally mix together to achieve the metallurgical bond. Ahigh degree of mixing between the cladding material and the substrate,which can deteriorate the properties of the resulting cladding layer,can be avoided using a laser cladding process. The laser claddingprocess can be automated and can be controlled to precisely coat aselective surface region of the apexes of the V-shaped, the U-shaped, orthe Z-shaped elements with a cladding layer of conductive metalconducive to the cathode shell, for example only, Ni, copper, oriron/iron alloy. The thickness of the cladding layer can be selecteddepending on the target structural properties and/or cosmetic properties(e.g., color, shininess and/or texture). The laser cladding process cancontrol the deposition of the cladding layer to achieve a desiredthickness varying between several micrometers to several millimeters.

A wide selection of homologous and non-homologous powder materials canbe used as the cladding material, and the materials can be selecteddepending on the target structural properties and/or cosmeticproperties. In some embodiments, the cladding material can include aconductive metal such as but not limited to nickel, copper, or stainlesssteel. The ratio of the cladding material to the substrate material canbe selected depending on the target structural properties and/orcosmetic properties. For example, increasing the loading of the nickelparticles in a metal matrix can achieve a harder, more brittle claddinglayer. Decreasing the loading of the nickel particles in the metalmatrix can achieve a cladding layer that is less brittle (i.e., lowerfracture toughness) and has a lower hardness. A harder cladding layercan be more resistant to abrasions, scratches and other wear, and a lessbrittle cladding layer can be more resistant to fracturing when subjectto impact forces during use of the anode assembly.

A laser cladding process can involve a 1-stage or a 2-stage process, asknown to one of skill in the relevant arts. In a 1-stage process, thecladding material may be applied during application of the laser beam(e.g., as a powder or wire fed alongside the laser beam). The powder canbe injected onto the substrate by either coaxial or lateral nozzlesrelative to the laser's position as known in the art. In a 2-stageprocess, the cladding material may be preplaced on the substrate surface(e.g., as preplaced powder, paste/binder mix, plate, wire, throughplasma spraying or flame spraying). The cladding material may be thenmelted onto the substrate using a laser beam. Thereafter, if desired,another clad layer can be deposited on top of the first clad layer toachieve a desired thickness or property of the final cladding layer.Either the laser beam or the substrate can be kept stationary while theother of the substrate or the laser beam is controlled to move in the x,y, z, directions so that the beam tracks along the surface of thesubstrate, locally melting the cladding material in the beam's path tobond the cladding material onto the substrate. In some embodiments, themetal substrate can be preheated before laser cladding, in order toreduce the cooling rates in the cladding layer and minimize or preventcracking of the layer on cooling.

The resulting cladding layer on the titanium contact strips or thetitanium apexes of the elements can be one or more stacked clad layers.In some embodiments, the cladding layer is one clad layer, and in someembodiments, the clad layer is a plurality of clad layers.

The laser cladded strips may be laser welded to the outside of theapexes of the elements attached to the titanium anode shell (e.g.through the longitudinal slots described above). The strips can beattached to the apexes before or after the elements are attached to thetitanium anode shell. Laser cladding may also provide a metallurgicalbond between the Ni—Ti. Laser cladding may provide lower part count andreduced cost as well as provide relatively wide contacts. Various lasercladding techniques are known and all are applicable herein. Exampleinclude, without limitation, laser cladding with co-axial powder, lasercladding with lateral feed powder, laser cladding with cold wire, lasercladding with hot wire, etc.

In some embodiments of the foregoing aspect and embodiments, the methodcomprises cladding the apexes of the V-shaped, the U-shaped, or theZ-shaped elements with the conductive metal such as, e.g. nickel. Inthis embodiment, the laser cladding of the nickel is performed directlyon the titanium apexes of the V-shaped, the U-shaped, or the Z-shapedelements. The laser cladding operation can be performed on the apexes ofthe elements either before the V-shaped, the U-shaped, or the Z-shapedelements are welded to the anode shell, or subsequent to welding.

In some embodiments of the foregoing aspect and embodiments, the methodcomprises coating the apexes of the V-shaped, the U-shaped, or theZ-shaped elements with the conductive metal such as, e.g. nickel. Insome embodiments, the coating is an electroless coating of the nickel onthe titanium apexes of the V-shaped, the U-shaped, or the Z-shapedelements.

In some embodiments of the foregoing aspect and embodiments, the methodcomprises manufacturing the plurality of V-shaped, U-shaped, or Z-shapedelements by explosion bonding or laser cladding nickel and titanium toform Ni—Ti sheets and configuring the Ni—Ti sheets to form the pluralityof V-shaped, U-shaped, or Z-shaped elements. The configuring may includecutting, polishing, bending etc. to achieve the desired shape of theelements.

In some embodiments of the foregoing aspect and embodiments, the methodcomprises providing electrical continuity through the conductive contactstrips, between the anode shell of the electrochemical cell with acathode shell of an adjacent electrochemical cell when theelectrochemical cells are stacked in an electrolyzer.

In some embodiments of the foregoing aspect and embodiments, the methodcomprises applying voltage to the anode and the cathode shell or passingcurrent through the cell.

In some embodiments of the foregoing aspect and embodiments, the methodcomprises providing vertical internal current bars inside the cathodeshell. In some embodiments of the foregoing aspect and embodiments, themethod comprises aligning each of the bases of the V-shaped, theU-shaped, or the Z-shaped elements in an alternate alignment with thevertical internal current bars and providing substantially uniformcurrent distribution across the one or more ion exchange membranes.

In some embodiments of the foregoing aspect and embodiments, the methodcomprises providing substantially uniform current distribution in theelectrochemical cell through the plurality of the V-shaped, theU-shaped, or the Z-shaped elements.

In some embodiments of the foregoing aspect and embodiments, the methodcomprises enabling air flow to provide convective cooling or heatingoutside the anode shell through the plurality of the V-shaped, theU-shaped, or the Z-shaped elements.

In some embodiments of the foregoing aspect and embodiments, the methodcomprises the anode comprising a corrugated porous anode having anamplitude of corrugation. In some embodiments of the foregoing aspectand embodiments, the method comprises contacting the plurality of theV-shaped, the U-shaped, or the Z-shaped elements to the outside of theanode shell such that the apexes of the elements are perpendicular tothe amplitude of corrugation of the corrugated porous anode. In someembodiments of the foregoing aspect and embodiments, the methodcomprises contacting the plurality of the V-shaped, the U-shaped, or theZ-shaped elements to the outside of the anode shell such that the apexesof the elements are parallel to the amplitude of corrugation of thecorrugated porous anode.

In one aspect, there is provided a process for manufacturing an anodeassembly, comprising attaching a plurality of V-shaped, U-shaped, orZ-shaped elements positioned outside an anode shell; and attaching ananode inside the anode shell. In some embodiments, the process comprisesmetallurgically attaching the plurality of the V-shaped, the U-shaped,or the Z-shaped elements outside the anode shell such that the pluralityof the V-shaped, the U-shaped, or the Z-shaped elements are inelectrical contact with the anode. In some embodiments, the processcomprises metallurgically attaching the plurality of the V-shaped, theU-shaped, or the Z-shaped elements outside the anode shell andmetallurgically attaching the anode inside the anode shell such that theplurality of the V-shaped, the U-shaped, or the Z-shaped elements are inelectrical contact with the anode. In some embodiments, each of theplurality of the V-shaped, the U-shaped, or the Z-shaped elementscomprise an apex and a base and each of the bases of the plurality ofthe V-shaped, the U-shaped, or the Z-shaped elements are attachedoutside the anode shell.

In some embodiments of the foregoing aspect and embodiments, the processcomprises providing conductive contact strips on the apexes of theV-shaped, the U-shaped, or the Z-shaped elements.

In some embodiments of the foregoing aspect and embodiments, the processcomprises coating the apexes of the V-shaped, the U-shaped, or theZ-shaped elements with nickel or copper, before or after the attachingstep.

In some embodiments of the foregoing aspect and embodiments, the processcomprises laser cladding the apexes of the V-shaped, the U-shaped, orthe Z-shaped elements with nickel or copper, before or after theattaching step.

In one aspect, there is provided a process for manufacturing anelectrochemical cell, comprising assembling an individualelectrochemical cell by joining together the anode electrode assemblyprovided herein with a cathode assembly comprising a cathode shell and acathode; placing the anode assembly and the cathode assembly in paralleland separating them by one or more ion exchange membranes; and supplyingthe electrochemical cell with feeders for a cell current and anelectrolysis feedstock.

In one aspect, there is provided a process for manufacturing orassembling an electrolyzer, comprising assembling individualelectrochemical cells as described herein and placing a plurality ofassembled electrochemical cells side by side in a stack and bracing themtogether so as to sustain electrical contact between the cells. In someembodiments, the electrical contact between the anode shell of oneelectrochemical cell and the cathode shell of the adjacentelectrochemical cell is through the conductive contact strips on theapexes of the V-shaped, the U-shaped, or the Z-shaped elementspositioned outside the anode shell. In some embodiments, the electricalcontact between the anode shell of one electrochemical cell and thecathode shell of the adjacent electrochemical cell is throughelectroless or electrolytic coating of nickel or copper, or lasercladded nickel or copper, or explosion bonded nickel or copper, orsprayed nickel or copper (or any other conducive conductive element) onthe apexes of the V-shaped, the U-shaped, or the Z-shaped elements.

The electron(s) generated at the anode are used to drive the reaction atthe cathode. The cathode reaction may be any reaction known in the art.The anode chamber and the cathode chamber are separated by the IEMs andthe intermediate frame provided herein that may allow the passage ofions, such as, but not limited to, sodium ions in some embodiments tothe cathode electrolyte if the electrolyte in the intermediate chamberis alkali metal halide solution such as sodium (or any other alkalimetal ion) chloride, sodium bromide, sodium iodide, sodium sulfate; orammonium ions if the electrolyte is ammonium chloride etc.; or anequivalent solution containing metal halide. In some embodiments, theIEMs and the intermediate frame allow the passage of anions, such as,but not limited to, chloride ions, bromide ions, iodide ions, or sulfateions to the anode electrolyte if the electrolyte in the intermediatechamber is e.g., alkali metal halide solution such as sodium chloride,sodium bromide, sodium iodide, or sodium sulfate or an equivalentsolution. The sodium ions may combine with hydroxide ions in the cathodeelectrolyte to form sodium hydroxide. The anions may combine with metalions in the anode electrolyte to form metal halide or metal sulfate.

In some embodiments of the electrochemical cell, the electrolyte (e.g.,alkali metal halide such as sodium (or any other alkali metal ion)chloride, sodium bromide, sodium iodide, sodium sulfate, or ammoniumchloride, HCl, or combinations thereof or an equivalent solution) isdisposed through the manifold into the intermediate frame between theAEM and the CEM. The ions, e.g. sodium ions, from the electrolyte passfrom the intermediate chamber through CEM to form e.g. sodium hydroxidein the cathode chamber and the halide anions such as, chloride, bromideor iodide ions, or sulfate anions, from the electrolyte pass from theintermediate chamber through the AEM to form HCl or a solution for metalhalide or metal sulfate in the anode chamber. The electrolyte, after thetransfer of the ions, can be withdrawn from the intermediate frame inthe intermediate chamber as depleted ion solution. For example, in someembodiments when the electrolyte is sodium chloride solution, then afterthe transfer of the sodium ions to the cathode electrolyte and transferof chloride ions to the anode electrolyte, the depleted sodium chloridesolution may be withdrawn from the intermediate frame in theintermediate chamber.

The following examples are put forth so as to provide those of ordinaryskill in the art with a complete disclosure and description of how tomake and use the present invention, and are not intended to limit thescope of what the inventors regard as their invention nor are theyintended to represent that the experiments below are all or the onlyexperiments performed. Various modifications of the invention inaddition to those described herein will become apparent to those skilledin the art from the foregoing description and accompanying figures. Suchmodifications fall within the scope of the appended claims. Efforts havebeen made to ensure accuracy with respect to numbers used (e.g. amounts,temperature, etc.) but some experimental errors and deviations should beaccounted for. Unless indicated otherwise, parts are parts by weight,molecular weight is weight average molecular weight, temperature is indegrees Centigrade, and pressure is at or near atmospheric.

EXAMPLES Example 1 Anode Assembly with Plurality of U-Shaped Elements

In this experiment, a comparison was made between the performance of twocells illustrated in FIGS. 9A and 9B. FIG. 9A illustrates a cell with ananode assembly that contained a sheet containing five U-shaped elementsattached outside the anode shell where the length of each U-shapedelement (“C” in the figures or the amplitude of the U-shape) was 36 mmand FIG. 9B illustrates a similar cell except that it contained verticalinternal current bars in the anode shell aligned with the verticalinternal current bars in the cathode shell. It was observed that whenthe cell of FIG. 9B was run for less than 1 hour at 300 mA/cm², AEMshowed significant damage (as shown in FIG. 10B) due to relatively highcurrent densities in the vicinity of the current bars. However, when thecell of FIG. 9A of the invention was used, the AEM showed no damage (asshown in FIG. 10A) even when the cell was run for about 20 hrs at 300mA/cm².

What is claimed is:
 1. An anode assembly, comprising: an anode shell; ananode positioned inside the anode shell; and a plurality of V-shaped,U-shaped, or Z-shaped elements positioned outside the anode shell and inelectrical contact with the anode.
 2. The anode assembly of claim 1,wherein each of the V-shaped, the U-shaped, or the Z-shaped elementscomprises an apex and a base.
 3. The anode assembly of claim 2, whereinthe U-shaped or the Z-shaped elements have a flat apex and the V-shaped,the U-shaped, or the Z-shaped elements have a flat base.
 4. The anodeassembly of claim 2, wherein the length between the apex and the base ofthe V-shaped, the U-shaped, or the Z-shaped element is between about5-30 mm.
 5. The anode assembly of claim 2, wherein the distance betweenthe apexes of adjacent V-shaped, adjacent U-shaped, or adjacent Z-shapedelements is between about 5-200 mm.
 6. The anode assembly of claim 2,wherein each of the bases of the V-shaped, the U-shaped, or the Z-shapedelements is metallurgically attached to the outside of the anode shellbringing it in electrical contact with the anode.
 7. The anode assemblyof claim 2, wherein the apexes of the V-shaped, the U-shaped, or theZ-shaped elements comprise conductive contact strips; are coated withnickel, copper, or iron; cladded with nickel, copper, or iron; sprayedwith nickel, copper, or iron; bonded with nickel, copper, or iron; orcombinations thereof.
 8. The anode assembly of claim 7, wherein theconductive contact strips comprise explosion bonded Ni—Ti, explosionbonded Cu—Ti, laser cladded Cu—Ti, or laser cladded Ni—Ti.
 9. The anodeassembly of claim 7, wherein the conductive contact strips provideelectrical continuity between the anode shell of an electrochemical cellwith a cathode shell of an adjacent electrochemical cell when theelectrochemical cells are stacked in an electrolyzer.
 10. The anodeassembly of claim 1, wherein the plurality of the V-shaped, theU-shaped, or the Z-shaped elements are individual elements or form asheet.
 11. The anode assembly of claim 1, wherein the plurality of theV-shaped, the U-shaped, or the Z-shaped elements provide substantiallyuniform current distribution to the anode.
 12. An electrochemical cell,comprising: the anode assembly of claim 1; a cathode shell, a cathodepositioned inside the cathode shell, and one or more ion exchangemembranes, wherein the one or more ion exchange membranes are disposedbetween the anode shell and the cathode shell.
 13. The electrochemicalcell of claim 12, wherein the cathode shell comprises vertical internalcurrent bars and wherein each of bases of the V-shaped, the U-shaped, orthe Z-shaped elements are in an alternate alignment with the verticalinternal current bars in the cathode shell so that the currentdistribution is substantially uniform across the one or more ionexchange membranes.
 14. An electrolyzer comprising multiplicity ofindividual electrochemical cells of claim
 12. 15. A method comprising:contacting an anode shell and an anode positioned inside the anode shellwith a cathode shell and a cathode positioned inside the cathode shellin an electrochemical cell; and contacting a plurality of V-shaped,U-shaped, or Z-shaped elements to the outside of the anode shell suchthat the anode shell is in electrical contact with the plurality ofV-shaped, U-shaped, or Z-shaped elements.
 16. The method of claim 15,wherein each of the V-shaped, the U-shaped, or the Z-shaped elementscomprises an apex and a base.
 17. The method of claim 16, furthercomprising metallurgically attaching each of the bases of the V-shaped,the U-shaped, or the Z-shaped elements to the outside of the anode shellthereby bringing it in electrical contact with the anode.
 18. The methodof claim 16, further comprising providing conductive contact strips onthe apexes of the V-shaped, the U-shaped, or the Z-shaped elements; orcoating, spraying, bonding, or cladding the apexes of the V-shaped, theU-shaped, or the Z-shaped elements with conductive metal.
 19. The methodof claim 18, further comprising laser cladding nickel or copper ontitanium or explosion bonding nickel or copper to titanium to form theconductive contact strips.
 20. The method of claim 18, furthercomprising providing electrical continuity through the conductivecontact strips, between the anode shell of the electrochemical cell witha cathode shell of an adjacent electrochemical cell when theelectrochemical cells are stacked in an electrolyzer.
 21. The method ofclaim 15, further comprising manufacturing the plurality of V-shaped,U-shaped, or Z-shaped elements by explosion bonding or laser claddingnickel and titanium to form Ni—Ti sheets and configuring the Ni—Tisheets to form the plurality of V-shaped, U-shaped, or Z-shapedelements.
 22. The method of claim 15, further comprising providingvertical internal current bars inside the cathode shell and aligningeach of the bases of the V-shaped, the U-shaped, or the Z-shapedelements in an alternate alignment with the vertical internal currentbars and providing substantially uniform current distribution across theone or more ion exchange membranes.
 23. The method of claim 15,comprising enabling air flow to provide convective cooling or heatingoutside the anode shell through the plurality of the V-shaped, theU-shaped, or the Z-shaped elements.